iMac - no sound output from internal speakers...

i have 4.1 sound system connected to my imac for months now, but today when trying to hear from the internal speakers i couldn't...

i noticed it first when it didn't allow me to control the volume with the apple remote (nor the keyboard keys for it). then i tried the system preferences and only digital output appears in the output devices. strangely, the headphones socket has that constant red light on, meaning it is in digital mode.
each time i plug in the speakers mini-jack to the output socket, device changes to headphone in system preferences.

can't really understand the logic of this... can anyone give me a help?
i'm gonna sell the mac in a couple of weeks, so this really happened in bad time...

I had this problem once. I had erased an HD on one of my mac's, and after, tried to play music while I was updating after OS install, I had noticed what you explain and I forgot to install the aluminum keyboard firmware. I had done so and all was well. Try this if you have not already and maybe problem solved.
Regards

well, i have here to possible solutions now (even if i feel more confident with the first one, before putting any alien object in the socket...).

i remembered i formated my imac to install 10.5 leopard with the surround speakers jack inside the socket, do you think that influenced anyhow? and i don't really know what the aluminum keyboard firmware is, and how it can be related to my system not recognizing the normal speakers output. another thing, i don't have an aluminium keyboard... still on a late '06 imac!

now the toothpick option... i'm a bit afraid of trying that (and possibly ruining everything!); but could you solve the problem after? did the speakers work again? any extra precaution to have when trying it?

If the red light is on inside the port when you pull out the headphones or speakers, the digital out is stuck in the on position. I'm not the first, nor will you be the last it's happened to.

I've read about using a toothpick, a q-tip, a straw, and several other things that folks have used to turn it off. You're not jamming the thing in there and exerting pressure on anything. No pressure, just sort of tickle it like it was a baby you're afraid of hurting. Or take it to Apple.

If the light is not on in the port when nothing is plugged in, then this is not your fix.

I cannot be held responsible for the things that come out of my mouth.
In the Windows world, most everything folks don't understand is called a virus.

No pressure, just sort of tickle it like it was a baby you're afraid of hurting. Or take it to Apple.

yep, i've just tried it, but nothing happened... light keeps on inside the port. sometimes i can make it turn off (i could even get the position where it always happens), but as soon as i move the "object" (first i tried with a toothpick, and after with a needle) the light goes on again.
taking it to apple is facing my budget problem, so will leave it for very last option.
i'll give it a second try tomorrow, and see what happens.

strangely when i could make the light off there was no sound coming out of the speakers still, but i could at least control the volume with keyboard shortcuts (even if with no practical result...). that makes me wonder if there isn't really any kind of setup/config failure, and if installing os x again wouldn't solve the problem.

well, keep on sending good energies and ideas, i hope i can really do this myself.

Have seen it reported at least twice that this little trick did not work and apple ended up having to repair it. I don't recall and am not a notebook tech, so don't know if they replaced the port or the systemboard.

I cannot be held responsible for the things that come out of my mouth.
In the Windows world, most everything folks don't understand is called a virus.

Hi,
I'm actually having the EXACT same problem with mine. It all started once I loaded Windows 7 via bootcamp (I should add this is the MSDNAA version and not a beta). The problems that i've noticed is that the output volume is really low, as the first poster mentioned and that the red light is always on. Also, the internal microphone doesn't work with steam but Windows does pick it up the mic if i go to "Control Panel -> Audio". I should add that I'm using the 2009 Macbook pro 13", 2.53Ghz model. Apparently Apple is using different hardware from Cirrus Logic as opposed to Realtek with the 2008 models. I am convinced that this is more of a driver issue.